The present invention relates generally to Magnetic Resonance Imaging, and more particularly, to a coil harness assembly for use in Magnetic Resonance Imaging.
Magnetic Resonance Imaging ("MRI") is a well-known procedure for obtaining detailed, two- and three-dimensional images of a patient based upon nuclear magnetic resonance ("NMR") principles. MRI is well suited for the imaging of soft tissues, and has been used primarily for diagnosing internal injuries or other medical ailments. A typical MRI system will generally include a magnet capable of producing a very strong homogenous magnetic field, sized to cover or surround a portion of a patient's anatomy; a radio frequency ("RF") transmitter and receiver system, including a receiver coil which surrounds the portion of the patient's anatomy under study; a magnetic gradient system to localize in space a particular portion of the patient's anatomy under study; and a computer processing/imaging system for receiving the signals from the receiver coil and for processing the signals into interpretable data, such as visual images for viewing by the physician or MRI attendant. Additional information regarding MRI technology and equipment can be found in Van Nostrand's Scientific Encyclopedia, Eighth Edition, pp. 2198-2201 and U.S. Department. of Heath and Human Services, "A Primer on Medical Device Interactions with Magnetic Resonance Imaging Systems," Feb. 7, 1997. The general principles and associated equipment used in MRI is well-known, and as such, additional disclosure is not necessary.
The advent of "open" MRI systems has provided patients with a more comfortable examination process and has also provided the MRI attendants and physicians access to the patient while a portion of that patient is being viewed by the MRI system. Examples of such open MR systems are the AIRIS.RTM. and AIRIS.RTM. II systems, commercially available from Hitachi Medical Systems America, Inc. Open MRI systems allow for physicians and other MRI attendants to perform an interventional surgery or other therapeutic procedures on the patient while the MRI system is producing images.
Open MRI systems also facilitate "MR Fluoroscopy" which combines near realtime signal acquisition, image reconstitution and image display with such interventional procedures. Accordingly, by utilizing MR Fluoroscopy, the physician will be able to monitor, substantially in real-time (approximately one image per second), a two- or three- dimensional image of the anatomy while performing a medical procedure on that anatomy. For example, if the physician wishes to insert an MR compatible tool, such as a needle or endoscope for example, into a particular organ, while missing other organs, the physician will be able to monitor the path of the endoscope, internally, by viewing the MRI image on a viewing screen.
Conventional coils for use with interventional MRI procedures typically include single-loop solenoid coil designs. Since these coils are very narrow (3-5 centimeters in width), the coils are inherently open and allow a large area for patient access. A disadvantage with such single-loop solenoid coils is that the types of interventional procedures performed with such a coil is limited. This is because the single loop solenoid coils tend to have an undesirable signal to noise ratio; and further, they do not provide a relatively large volume of coverage. Accordingly, such a single loop solenoid coil would not be desired in an interventional procedure where an endoscopic instrument will enter into the patient's body at an oblique angle, for example.
Quadrature coil ("QD") arrangements provide a desirable signal to noise ratio. However, a disadvantage of using such QD arrangements in interventional procedures is that the coil harnesses for housing the coils and for positioning the coils about the portion of the patient being examined often prevent direct access to that portion of the patient by the physician. For example, a conventional spine/body coil harness for a QD arrangement includes a substantially rectangular base with an imperforate coil flap extending laterally from each side thereof. The two flaps wrap about the body of the patient and meet above the patient to form a continuous, imperforate loop about the patient. Accordingly, because these flaps substantially enclose the portion of the patient's anatomy being examined, interventional access to this portion of the patient is limited.
Accordingly, there is a need to provide a QD harness that has been modified to provide an optimized access to the patient during the MRI viewing process, and in particular, during MR Fluoroscopy.